3 pt. won't hold arms down

[HeavyToy]

Re: 3 pt. won\'t hold arms down

Well that makes sense. That debate would have ended a lot sooner if page title had not been abbreviated.

The follow-up linkage follows the kinematics of the 3 pt hydraulic lever and does what? Does it stop the hydraulic flow at the upper and lower limits of the hydraulic levers/arms?

 

[RickB]

Re: 3 pt. won\'t hold arms down

When adjusted properly, the follow-up linkage returns the control valve to neutral when the rockshaft position matches that of the quadrant lever. Most importantly, it returns the control valve to neutral when the rockshaft reaches its upper limit. properly adjusted, you should be able to lift the hitch and rockshaft up a very little bit when the quadrant lever is full up.

 

[HeavyToy]

Re: 3 pt. won\'t hold arms down

So without the follow-up linkage connecting and communicating the position of the rockshaft to the follow-up lever, the pumps continue to build pressure even though the rockshaft will have reached its limit of travel.

I have not used my tractor since discovering the broken part. I planned to reinstall the part when it arrives. As you can tell, this is my first tractor. Is the adjustment something that I can set myself? Once the positions are established, should I apply a non-permanent Locktite to the threads?

When I set the nuts in front and behind the little swivel bracket (item #20 in the illustration) will they capture it front and back or will the bracket have some travel between the two nut positions?

Will I be adjusting the linkage relative to the upper limits of travel for the rockshaft? Should I allow the rockshaft to travel to the upper limit and then back off slightly and then secure the positions of the nuts? If yes, what is my frame of reference for determining the amount of travel that I should back off?

 

[RickB]

Re: 3 pt. won\'t hold arms down

I believe you can adjust the linkage successfully. I don't use Loctite here, but it won't hurt. The nuts will jam up tightly to either side of the bracket; hence my nonuse of Loctite. You will be making the adjustment relative to the rockshaft upper limit. With the linkage disconnected and tractor idling, raise the quadrant lever fully. The hitch should raise full up, and you should hear the engine labor as the pump output is forced over the relief valve. Shut off the tractor, connect the linkage and lengthen it until the rockshaft arms come up somewhere near an inch or so shy of their upper physical limit as determined by raising them by hand. Obviously, you have to run the tractor to test, but shut it off to adjust the linkage to avoid injury. The tractor should not labor, and the hydraulic system should not be running over relief when the quadrant lever is full up. Hope this is sufficiently clear.

 

[HeavyToy]

Re: 3 pt. won\'t hold arms down

Thank you for sharing your knowledge as well as your patience.

 

[jinman]

Re: 3 pt. won\'t hold arms down

I just realized I have a picture of this limit adjustment on my tractor. It's attached. My guess is your's is very similar.

 

[HeavyToy]

Re: 3 pt. won\'t hold arms down

Just an update:

The linkage on the broken "L" bracket actually controls the upward travel of the rock shafts. Acts as a light draft mechanism. The problem that was the imputes for the original thread was that the rock shafts would flop upward and not float upwards. This being my first tractor, I new there was a change but I could not convey the extent. Once I replaced the bracket, and coaxed the flow control lever (draft control or similar) forward with a rubber mallet (jammed from the forces that broke the bracket), the rock shafts now float when the implements see resistance.

Also, the noisy hydraulics, that I had posted questions about earlier, were also linked to the broken "L" bracket, as when the 3 pt. hitch was raised fully, the position of the rock shafts was not communicated through the linkage to the flow control valve and the pump would be whining away. When I back down a bit it would hold fine but the pump would still be drawing power to hold the position (I think).